Energias renovables

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  • Publicado : 11 de noviembre de 2010
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I am going to speak about renewable energies. The world needs a lot of energy and depends on it, so the Renewable Energy is a good alternative to fosil fuels. Also, they produce little or nopollution or greenhouse gases and finally, they will never run out.
Some types of Renewable Energy
Hydropower
Hydropower is the largest source of renewable energy. Most of this water comes from rivers andis released through turbines to produce energy. Although this power source does not release pollution, it can possibly harm fish and wildlife, displace people, and alter the quality of water.Biomass/Bioenergy
Biomass fuels stem from industrial processing, such as forestry and wood products and agriculture. It can replace coal in power plants because it produces less sulfur dioxide than coal.Geothermal Energy
Geothermal energy is produced from naturally occurring steam and hot water from under the Earth’s surface. The steam rotates a turbine, which in turn powers an electric generator.Also, hot water can be used to directly heat buildings. The downside to geothermal energy is that land sites are very hard to find and extremely rare. A positive fact is that geothermal energy isvery cost effective and reliable.
Wind Energy
The wind rotates blades around a hub, which is connected to the main shaft. The main shaft spins a generator. The size of turbines is determined by howmuch energy is needed.
The disadvantages of wind energy are that again, the technology is very expensive, the machinery is known to be noisy, birds have been killed by running into the turbines, andthe wind might not be present at certain times throughout the year.
Photovoltaics (PV) Cells
PV cells produce electricity from sunlight. These materials absorb sunlight, which frees the electronsfrom their atoms and allows them to generate electricity.
PV cells are great because they don’t require high maintenance, are very reliable, and don’t produce pollutants.
The downside to this power...
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